This blog covers the day to day progress of water rocket development by the Air Command Water Rockets team. It is also a facility for people to provide feedback and ask questions.

Friday, November 25, 2011

Shadow pressure test, and deployment mechanism

We have been making good progress on the Shadow. During the week we tested the deployment mechanism and made a short video of how it works.

Today we pressure tested the launcher and rocket to the full initial launch pressure. This was the first time we had the rocket and launcher up to this pressure, so we were happy when everything worked. We even tried to see how hard it will be to launch the rocket at the full pressure. This was nice and easy and shouldn't be an issue on launch day.

The recent updates from the last week have been posted to our main website with photos here:

The update also includes the deployment mechanism video.


Vicente Garcia M Junior said...

Dear friend George "Shadow" is getting very good. No doubt the team is once again AirCommandRockets innovating. With the "Shadow" you're rewriting the history of the rockets of water, giving a new dimension to the subject.
We water rocket enthusiasts have much to thank you guys.

I wish you success.

George Katz said...

Thanks for the nice words Vicente, but there really is nothing new in the Shadow. All the techniques we are using have been developed and used by many others, especially in the model rocket community. We are simply adapting some of the construction techniques to be used in water rockets. We are publishing the details of the build so that others can avoid the same mistakes we make along the way.

It's getting close to 6 months now since we started working on the rocket. ... It's time to get it finished. :)

Unknown said...

Hey George,

That deployment system really is impressive :) if that doesn't get the chute out quickly I don't know what will :P

Do you reckon the shadow may go near supersonic i can just see 500psi on a very sleek and light rocket like that it may be close?

Regards Doug

George Katz said...

Hi Doug,

The Shadow will go nowhere near mach. Running the sims at 500psi gives a peak velocity of 107m/s (385kmh / 240mph) which is around mach 0.32. But that's what the sims say, in real life it will be probably lower than that. We should be able to calculate the velocity from the altimeter data to see how quickly it was rising.

If it blows up on the pad, certain pieces may briefly come close to mach :P

Unknown said...

Hey George,

That speed surprises me I honestly thought it would go faster :P

Shows what I know eh? :)

Regards Doug

jkdenham said...

335psi is impressive, you are really stepping up the level production and engineering on the Shadow project. It has been a good project to follow.

At least the rain has stopped and we can go flying again.

All the best with the launch, George

George Katz said...

hi Jeremy, Yes finally the rain has stopped. We're hoping for some good weather and blue skies for the next launch window opportunity. There is only one more launch this year with NSWRA.

Michael Kelley said...

athis is a great website,and you are doing a wonderful job on the shadow,I cant wait for more updates!
thank you

George Katz said...

Thanks for your support Mike. :) We usually try to do the updates every few days, if we are making progress that is. It's been a bit busy here lately with non-rocket related projects.

Jan said...

Hi George,
Ever thought about the risk of high temperatures of the rocket?

I was yesterday on a course regarding Fibre Reinforced Polymers in the construction industry.
There I learned that epoxys / polymers loses a lot of there strength at temperatures above 60°C, the glass transition temperatures of polymers in glass fibre and carbon fibre reinforced polymers.
(see also "Glass transition" on wikipedia).
It will be very important to keep the rocket cool during compression and waiting for the launch.

greetings, Jan

George Katz said...

Hi Jan,

Yes, temperature can affect the strength of the epoxy. Although, the majority of the overall strength of the pressure chamber is provided by the glass. But you are right we will be filling the rocket slowly to keep things cool(er). The end caps are made of PVC which can also weaken when heated. This is one drawback of doing a hydro test. You just don't get the same conditions as on launch day.


- George